Good afternoon! I bought the Hantek DSO5072P oscilloscope, and was distressed when I saw that it hangs when the signal disappears. My problem- on the video, what can it be? What is the problem?
Video: https://youtu.be/gCpmYfNtfkg

I do not see any problem. Your oscilloscope is working fine. Carefully read the user guide for the description of the trigger operation in the auto-scan mode. There it is described. If you do not want to have these friezes when the signal disappears, you can raise the trigger level above the signal level and everything, but in this case the signal synchronization will not work.